1. Field of the Invention
This invention relates generally to solid material comminution or disintegration, and more particularly to a paper shredder with separation or classification of material into a plurality of partitions or end walls.
2. Description of the Related Art
Paper shredders are used to protect the confidential information that would otherwise potentially be lost when papers containing such information are disposed of through conventional residential or business refuge removal. One of the easiest methods of conducting business or personal espionage is called xe2x80x9ctrash trawling,xe2x80x9d xe2x80x9cdumpster diving,xe2x80x9d xe2x80x9cwaste archeology,xe2x80x9d or simply xe2x80x9ctrashing.xe2x80x9d All refer to rifling through curbside garbage, set out for refuge pickup, in an effort to cull valuable information on a business or person from their trash.
Paper shredding devices have been used for years to prevent the compromise of the information contained in personal and business papers (See for example U.S. Pat. No. 929,960, xe2x80x9cWaste-Paper Receptacle,xe2x80x9d 3 Aug. 1909). Most paper destruction devices in use today operate using paired rotary cutting elements and fall into one of three categories: strip cutter, the most basic type of shredder, where the paper is cut into strips; cross cutters, where the paper is cut both in-line with the direction of insertion into the shredder and across that dimension; and disintegrators, which have sets of rotating cutting elements that simply randomly cut the paper until the shredded pieces are small enough to be able to fall through a screen below the cutting elements.
The efficacy of a paper shredder in preventing the reassembly, and hence compromise, of the shredded document is, among other things, dependent on the size of the shredder residue, with smaller average residue size being more secure and larger residue size being less secure. This is akin to the difficulty of a jigsaw puzzle being partially dependent on the size of the puzzle pieces. Unfortunately, given all of the pieces and enough time and effort, any puzzle or document can be reassembled.
The greatest weakness of paper shredders is that all of the pieces of all of the shredded documents are available in the effluence of the shredder. In normal residential or business operation the effluence of the paper shredder is collected in a refuge receptacle of some kind, usually a trash bag, and this trash bag is disposed of, through conventional disposal means only when it fills. A dumpster diving adversary then has access to the complete wholes of all the shredded documentsxe2x80x94in fact in selecting documents for shredding the user may have pre-sorted the most sensitive documents for the adversary.
It might appear that an adversary""s biggest difficulty would be sorting the residue into those portions which belongs to each piece of paper shredded but the operation of paper shredders makes this sorting much less difficult than is initially apparent. Paper shredders are by and large serial devices. They accept only a few sheets of paper, at most, for simultaneous shredding, with the higher security shredders accepting the fewest simultaneous sheets. After passing through the shredder mechanism, the shredded pages fall, or are otherwise transported, into the refuge receptacle and form a stratum in a stratified stack of individual document residue in the receptacle. The individual strata of documents written on paper of varying types or colors are easily discernable in the stratified stack. This discernable stratification makes the separation of the refuge receptacle residue into that residue attributable to individual document pages a much easier task for an adversary.
Further, some of the practical operating considerations of modern shredders make this even easier. High security shredders use multiple very high speed cutting elements to shred office paper rapidly into many thousands of pieces. This rapid cutting produces a great deal of paper dust and often leaves the paper residue with an electrostatic charge which causes the residue to stick to the shredder mechanisms instead of exiting the shredder as an effluence. See U.S. Pat. No. 4,893,759, Paper Shredder With Charge Removing Means,xe2x80x9d which is hereby incorporated in its entirety. The cutting heads of these cutting elements rapidly dull and the motive elements behind them rapidly wear if not properly lubricated and flushed to remove dust from the moving parts.
To combat the dulling of the cutting elements and to lubricate and clean the motive elements of the shredder these parts are usually well lubricated with oil. Many modern shredders even include systems for automatically oiling these parts (See for example U.S. Pat. No. 5,186,398, xe2x80x9cPaper Shredderxe2x80x9d). As a result of this lubrication, the shredder effluence is often also coated with oil. This causes the residue to stick together and hence helps ensure that the individual document stratums of residue are not mixed in the stratified stack of residue.
Some shredders are equipped with a wetting system to help suppress the paper dust generated and to cause a denser packing of the effluence. See, for example, U.S. Pat. application 20020017577, xe2x80x9cMobile Paper Shredder System.xe2x80x9d The wetting of the effluence, much like the oil coating, causes the residue to stick together and hence also suppresses mixing of individual document stratums in the stratified residue stack.
Stratification of shredder residue, the infusion of liquids into the residue, and the shredding of papers of differing types and colors all make reassembly of shredded documents easier but, as noted above, given access to all of the shredder residue of a document, that document can be reconstructed with enough effort.
It has been suggested that the addition of a mechanical auger, deployed in the refuge receptacle, or in the instant invention in each of the refuge receptacles, to stir the residue thereby destroying the stratification of the residue would add significantly to the security of the shredder. Unfortunately, the added complication and need to remove the auger mechanism before disposal of the material in the refuge receptacle have weighed against this improvement.
An object of the present invention is to provide a shredder residue dispersion system where shredder residue from each document shredded is directed into multiple residue receptacles for separation of the document residue to thwart reassembly.
In order to attain the objectives described above, according to an aspect of the present invention, there is provided a shredder residue dispersion system whereby the effluence of a paper shredder is directed into multiple residue receptacles which may then be disposed of in a manner to designed to make acquisition of all of residue of any one particular document more difficult than had the effluence not be separated.
The shredder residue dispersion system increases the security of a standard shredder by dispersing the shredded paper into multiple bins on a continuous basis. This ensures that no one document will be complete in any one residue bag. This can be coupled with a procedure of disposing of only one residue bag at a time on a rotating basis, of geographic dispersion in the disposal of the bags, or of combination of diverse time and location dispersion, to ensure that no adversary could collect the entire shredded document at any one time or in any one place.
The instant invention uses a deflector plate and multiple bins lined with bags to disperse and collect shredder residue. The material is usually gravity fed from the bottom of the cutting elements to the deflector plate. The plate ensures that the residue material does not back up into the cutting elements and ensures that the material enters the multiple collection bins. The deflector plate overlaps the bins so that no shredder residue will fall between the collections bins. The multiple bins fit underneath the deflector plate and are lined with residue collection bags.
The aforementioned features, objects, and advantages of this method over the prior art will become apparent to those skilled in the art from the following detailed description and accompanying drawings.